Feds say global warming one of the key threats to iconic western trees
By Summit Voice
SUMMIT COUNTY — Climate change is one of the factors threatening whitebark pine, U.S. Fish and Wildlife Service biologists said last month, declaring that the iconic high altitude tree of the northern Rockies needs endangered species protection. But even though the agency acknowledged that the tree could become extinct in less than 200 years, it won’t be listed because other species are a higher priorities.
Along with global warming, whitebark pines are threatened by habitat loss, white pine blister rust, mountain pine beetles and catastrophic wildfires.
For now, whitebark pines will be listed as a candidate species, joining hundreds of other plants and animals on a waiting list. Candidate status doesn’t confer any special protections to whitebark pines, but does encourage federal agencies to cooperate on voluntary conservation measures.
Saving the trees is going to be a race against time with or without a listing. There is no known way to stop whitebark pine mortality caused by white pine blister rust and mountain pine beetle. However, the U.S. Forest Service and other partners have made important strides in understanding the white pine blister rust ecology and mountain pine beetle life history. The U.S. Forest Service is growing and planting whitebark seedings that are resistant to the non-native blister rust fungus.
In the big picture, whitebark pine is experiencing an overall long-term pattern of decline, even in areas originally thought to be mostly immune from threats. Recent predictions indicate a continuing downward trend within the majority of its range. While individual trees may persist, given current trends the Service anticipates whitebark pine forests will likely become extirpated and their ecosystem functions will be lost in the foreseeable future. On a landscape scale, the species appears to be in danger of extinction, potentially within as few as two to three generations.The generation time of whitebark pine is approximately 60 years.
The Fish and Wildlife Service said it’s aware that the potential demise of whitebark pines raises some concern about grizzlies, who use whitebark pine as a food source. But the agency said 25 years of data show grizzly bears are not dependent on whitebark pine seeds for their survival. Because whitebark seeds are not a naturally reliable food source, grizzlies have been coping for millennia by switching to other foods when whitebark pine seeds are unavailable by consuming other readily available foods such as ungulates, ground squirrels, insects, roots, mushrooms, and other vegetative matter. Therefore, the Service does not believe this finding will impact grizzly bear recovery.
Whitebark pine typically occurs on cold and windy high-elevation or high-latitude sites in western North America. It is considered a keystone species because it increases biodiversity and contributes to critical ecosystem functions. Whitebark pine is frequently the first conifer to become established after disturbances like wildfires and subsequently stabilizes soils and regulates runoff. Snow drifts around whitebark pine trees, increasing soil moisture, modifying soil temperatures, and holding soil moisture later into the season. Whitebark pine frequently shade, protect, and slow the progression of snowmelt, essentially reducing spring flooding at lower elevations. Whitebark pine also provides important, highly nutritious seeds for numerous birds and mammals.
About 44 percent of the species’ range occurs in the United States in Wyoming, Montana, Idaho, Nevada, California, Oregon, and Washington. The remaining 56 percent of the species range occurs in British Columbia and Alberta, Canada. Whitebark pine is a slow-growing, long lived tree with a life span of upwards of 500 years and sometimes more than 1,000 years. Because whitebark pine seeds cannot be wind-disseminated, primary seed dispersal occurs almost exclusively by Clark’s nutcrackers. Consequently, Clark’s nutcrackers facilitate whitebark pine regeneration and influence its distribution and population structure through their seed caching activities.
Visit the USFWS online to learn more about the status of whitebark pine, or contact the Wyoming Ecological Services Field Office, U.S. Fish and Wildlife Service, 5353 Yellowstone Road Suite 308A, Cheyenne, WY 82009, phone (307) 772-2374.